This series originated during a visit of prof. K. G. Mukerji to the CNR Plant Protection Institute at Bari, Italy, in November 2005. Both editors convened to produce a series of five volumes focusing, in a multi-disciplinary approach, on recent advances and achievements in the practice of crop protection and integrated pest and disease management. This fourth Volume deals with management of nematodes parasitic of tree crops, and includes a section on tropical fruit crops and commodities, as well as a second section on tree crops from more temperate areas. The latter also includes a chapter updating the current knowledge about the pine wood nematode, Bursaphelenchus xylophilus. Volume 4 flanks Volume 2 of this IMPD series, which focused on management of vegetable and grain crops nematodes. Nematodes are a very successful, diversified and specialised animal group, present in nature in any ecological niche. Among nematode species, only a reduced number feeds on plants, of which a few species cause severe economic impacts on crop productions. Plant parasitic nematodes represent an important concern for a broad range of agricultural productions and systems, worldwide. This statement explains the attention devoted in last decades to nematodes, and the research and technical efforts invested for their control.